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You searched for: subject:"prototypes"
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[audio]Prototypes Kaleidoscope
Prototypes - Kaleidoscope
Keywords: Prototypes - Kaleidoscope
Downloads: 9
[texts]Selection of Lockheed Martin's Preferred TSTO Configurations for the Space Launch Initiative - Hopkins, Joshua B
Lockheed Martin is developing concepts for safe, affordable Two Stage to Orbit (TSTO) reusable launch vehicles as part of NASA s Space Launch Initiaiive. This paper discusses the options considered for the design of the TSTO, the impact of each of these options on the vehicle configuration, the criteria used for selection of preferred configurations, and the results of the selection process. More than twenty configurations were developed in detail in order to compare optioiis such as propellant ...
Keywords: RESEARCH AIRCRAFT; HISTORIES; PROTOTYPES
Downloads: 152
[texts]Development of infrared sensors using energy transfer/energy upconversion processes: Study of laser excited fluorescence in rare Earth ion doped crystals - Nash-Stevenson, S. K.
A summary is presented of the spectroscopic study of three systems: LaF3:Ho(3), LaF3:Er(3) and CaF2:Nd(3). When the D levels of Ho(3) in LaF3 were resonantly excited with a laser beam of 640 nm, upconverted emissions were detected from J (416 nm), F (485 nm), and E (546 nm) levels. Energy upconverted emissions were also observed from F and E levels of Ho(3) when the material was excited with an 800 nm near infrared laser...
Keywords: SCHEDULES; SPACECRAFT CONTROL; TELEMETRY; PAYLOADS; PROTOTYPES; WORKSTATIONS
Downloads: 78
[texts]Photographic Analysis Technique for Assessing External Tank Foam Loss Events - Rieckhoff, T. J.
A video camera and recorder were placed inside the solid rocket booster forward skirt in order to view foam loss events over an area on the external tank (ET) intertank surface. In this Technical Memorandum, a method of processing video images to allow rapid detection of permanent changes indicative of foam loss events on the ET surface was defined and applied to accurately count, categorize, and locate such events.
Keywords: MECHANIZATION; PROGRAMMING LANGUAGES; PROVING; AXIOMS; PROTOTYPES
Downloads: 55
[texts]A Study of the Non-Thermal X-Ray Emission of Shell-Type Supernova Remnants - Allen, Glenn E
The term of the second year of the award is the period from March 15, 2001 to March 14, 2002. As was the specified goal of the second year, we analyzed the spatial and spectral X-ray data for several young supernova remnants. I published a paper about an analysis of the ROSAT, ASCA, and RXTE data for the supernova remnant SN 1006. A copy of this paper is enclosed. As described in the paper, we believe that we accurately modeled the nonthermal X-ray emission from the remnant...
Keywords: PROPULSION; REUSABLE LAUNCH VEHICLES; PROTOTYPES; ROCKET ENGINES
Downloads: 65
[audio]Prototypes on AFTERSHOCK
A radio interview with Prototypes on the AFTERSHOCK program on 106.9 Vox FM Recorded on 19/2/14
Keywords: Prototypes; Vox FM; AFTERSHOCK; DJ Styx; 106.9
Downloads: 6
[texts]Ground-Laboratory to In-Space Effective Atomic-Oxygen Fluence Determined for DC 93-500 Silicone - deGroh, Kim K.
Surfaces on the leading edge of spacecraft in low Earth orbit (e.g., surface facing the velocity direction), such as on the International Space Station, are subject to atomic oxygen attack, and certain materials are susceptible to erosion. Therefore, ground-based laboratory testing of the atomic oxygen durability of spacecraft materials is necessary for durability assessment when flight data are not available...
Keywords: ROBUSTNESS (MATHEMATICS); RUNWAYS; PRECISION; PROTOTYPES; SPACING; AIRPORTS; ROUTES
Downloads: 105
[texts]Design, development and prototype fabrication of an area hydrogen detector monthly progress report, 1 oct. 1963 - 31 oct. 1963 - Michaels, P. A
Hydrogen detector
Keywords: FABRICATION; GAS DETECTORS; HYDROGEN; OPTICAL SCANNERS; PROTOTYPES; DETECTOR; HYDROGEN
Downloads: 103
[texts]A model for merging software prototypes - Dampier, David A.;Luqi.
Cover title
Keywords: PROTOTYPES; SOFTWARE ENGINEERING; COMPUTER PROGRAMS; COMPUTER PROGRAM VERIFICATION; ASSIMILATION
Downloads: 21
[texts]Linking Horizontal And Vertical Transports of Biomass Fire Emissions to the Tropical Atlantic Ozone Paradox during the Northern Hemisphere Winter Season: II. 1998-1999. - Jenkins, Gregory S.
The horizontal and vertical transport of biomass fire emissions in West Africa during November 1998 through February 1999, are examined using all available data including wind, fire, aerosol, precipitation, lightning and outgoing longwave radiation. Ozonesonde data from the Aerosols99 Trans-Atlantic cruise are also included with rain and wind analyses. The results here support earlier studies that ozone and ozone precursors associated with biomass burning are confined to the lower troposphere pr...
Keywords: AUTONOMY; DECISION MAKING; INFORMATION ANALYSIS; BEHAVIOR; DECISION THEORY; PROTOTYPES
Downloads: 74
[texts]xerox :: sdd :: memos 1977 :: 19771013 October Status Report For Advanced Design And User Prototypes Group
From the bitsavers.org collection, a scanned-in computer-related document.xerox :: sdd :: memos 1977 :: 19771013 October Status Report For Advanced Design And User Prototypes Group
Keywords: design; prototypes; prototyping; ibm; user; walkthrough; specification; janus; interface; smalltalk
Downloads: 20
[texts]NASA Technology Benefits Orthotics - Myers, Neill
Engineers at NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama have designed a knee brace to aid in the rehabilitation of medical patients. The device, called the Selectively Lockable Knee Brace, was designed for knee injury and stroke patients but may potentially serve in many more patient applications. Individuals with sports related injuries, spinal cord injuries and birth defects, such as spina bifida, may also benefit from the device...
Keywords: BROADCASTING; PARALLEL PROCESSING (COMPUTERS); PROTOTYPES; DATA STRUCTURES; MESSAGES; TILES; PREPROCESSING
Downloads: 76
[texts]Biotechnology Facility: An ISS Microgravity Research Facility - Gonda, Steve R.
The International Space Station (ISS) will support several facilities dedicated to scientific research. One such facility, the Biotechnology Facility (BTF), is sponsored by the Microgravity Sciences and Applications Division (MSAD) and developed at NASA's Johnson Space Center. The BTF is scheduled for delivery to the ISS via Space Shuttle in April 2005. The purpose of the BTF is to provide: (1) the support structure and integration capabilities for the individual modules in which biotechnology e...
Keywords: KERNEL FUNCTIONS; COMPONENT RELIABILITY; SUPERCOMPUTERS; VOIDS; PROTOTYPES; MIGRATION
Downloads: 73
[texts]A Framework for Managing Inter-Site Storage Area Networks using Grid Technologies - Kobler, Ben
The NASA Goddard Space Flight Center and the University of Maryland Institute for Advanced Computer Studies are studying mechanisms for installing and managing Storage Area Networks (SANs) that span multiple independent collaborating institutions using Storage Area Network Routers (SAN Routers). We present a framework for managing inter-site distributed SANs that uses Grid Technologies to balance the competing needs to control local resources, share information, delegate administrative access, a...
Keywords: INTERFEROMETERS; METROLOGY; DEGREES OF FREEDOM; THEODOLITES; PROTOTYPES; SENSITIVITY; ROTATION; ELEVATION
Downloads: 91
[texts]Phototyping with application generators : lessons learned from the Naval Aviation Logistics Command Management Information System case - Bui, Tung X., 1953-;Blake, Cheryl D.;Emery, James C.
Cover title
Keywords: MANAGEMENT INFORMATION SYSTEMS; NAVAL AVIATION; PROTOTYPES; NAVAL LOGISTICS
Downloads: 31
[texts]Numerical Study of the Role of Shallow Convection in Moisture Transport and Climate - Seaman, Nelson L.
The objective of this investigation was to study the role of shallow convection on the regional water cycle of the Mississippi and Little Washita Basins of the Southern Great Plains (SGP) using a 3-D mesoscale model, the PSU/NCAR MM5. The underlying premise of the project was that current modeling of regional-scale climate and moisture cycles over the continents is deficient without adequate treatment of shallow convection...
Keywords: AUTOMATIC WEATHER STATIONS; OPTICAL RADAR; PROTOTYPES; DEPLOYMENT; ANTARCTIC REGIONS; AUTONOMY
Downloads: 122
[texts]Coated oxidizers for stability in space propulsion rockets - NON
No Abstract Available
Keywords: ENGINE TESTS; PROTOTYPES; STIRLING CYCLE; AUTOMOBILE ENGINES; HELIUM
Downloads: 99
[texts]Design and Predictions for High-Altitude (Low Reynolds Number) Aerodynamic Flight Experiment - Greer, Donald
A sailplane being developed at NASA Dryden Flight Research Center will support a high-altitude flight experiment. The experiment will measure the performance parameters or an airfoil at high altitudes (70,000 - 100,000 ft), low Reynolds numbers (2 x 10(exp 5) - 7 x 10(exp 5)), and high subsonic Mach numbers (0.5 and 0.65). The airfoil section lift and drag are determined from pilot and static pressure measurements...
Keywords: AUTONOMY; SPECIFICATIONS; GROUND SUPPORT SYSTEMS; AUTOMATIC CONTROL; PROTOTYPES; SPACECRAFT CONTROL
Downloads: 126
[texts]Premixed Prevaporized Combustor Technology Forum - NON
The Forum was held to present the results of recent and current work intended to provide basic information required for demonstration of lean, premixed prevaporized combustors for aircraft gas turbine engine application. Papers are presented which deal with the following major topics: (1) engine interfaces; (2) fuel-air preparation; (3) autoignition; (4) lean combustion; and (5) concept design studies.
Keywords: CENTRIFUGES; PIEZOELECTRICITY; SHAKERS; ACTUATORS; EARTHQUAKES; PROTOTYPES; SEISMIC WAVES
Downloads: 135
[texts]Space Shuttle ET Friction Stir Weld Machines - Thompson, Jack M
NASA and Lockheed-Martin approached the FSW machine vendor community with a specification for longitudinal barrel production FSW weld machines and a shorter travel process development machine in June of 2000. This specification was based on three years of FSW process development on the Space Shuttle External Tank alloys, AL2 195-T8M4 and AL22 19-T87. The primary motivations for changing the ET longitudinal welds from the existing variable polarity Plasma Arc plasma weld process included: (1) Sig...
Keywords: MARS SURFACE; ROVING VEHICLES; INSTRUMENT ORIENTATION; AUTONOMY; PROTOTYPES
Downloads: 136
[texts]Continuous Risk Management Course - Hammer, Theodore F
This document includes a course plan for Continuous Risk Management taught by the Software Assurance Technology Center along with the Continuous Risk Management Guidebook of the Software Engineering Institute of Carnegie Mellon University and a description of Continuous Risk Management at NASA.
Keywords: ALGORITHMS; PROGRAM VERIFICATION (COMPUTERS); THEOREM PROVING; PROTOTYPES; DOMAINS
Downloads: 273
[image]Model No. 98

Keywords: Europe; Shoes; Leather; Metropolitan Museum of Art; French; France; leather, wood; 1939; Prototypes
Downloads: 22
[texts]Towards G2G: Systems of Technology Database Systems - Maluf, David A.
We present an approach and methodology for developing Government-to-Government (G2G) Systems of Technology Database Systems. G2G will deliver technologies for distributed and remote integration of technology data for internal use in analysis and planning as well as for external communications. G2G enables NASA managers, engineers, operational teams and information systems to ''compose'' technology roadmaps and plans by selecting, combining, extending, specializing and modifying components of tec...
Keywords: MANAGEMENT METHODS; AIR TRAFFIC CONTROL; FIELD TESTS; AIRPORTS; PROTOTYPES; SPACING; TRAFFIC
Downloads: 64
[texts]Aircraft Noise Perception Study in Brazil: A Perspective on Airport Sustainable Growth and Environmental Awareness - deArantesGomesEller, Rogerio
Aircraft noise perception is related to several variables that are tangible and objective, such as the number of operations, flight schedules. Other variables, instead, are more subjective, such as preferences. However, although their elusiveness, they contribute to determine the individuals' perception of this type of externality. Despite the fact that the complaints related to aeronautical noise have been registered since the decade of 50, it has been observed that the perception of noise seem...
Keywords: AUTOMATA THEORY; SOFTWARE ENGINEERING; FORMALISM; COMPUTER PROGRAMMING; PROTOTYPES; ADAPTATION; REACTIVITY; SIMULATION
Downloads: 55
[texts]The NASA master directory quick reference guide - NON
The NASA Master Directory (MD) is a free, online, multidisciplinary directory of space and Earth science data sets (NASA and non-NASA data) that are of potential interest to the NASA-sponsored research community. The MD contains high-level descriptions of data sets, other data systems and archives, and campaigns and projects. It provides mechanisms for searching for data sets by important criteria such as geophysical parameters, time, and spatial coverage...
Keywords: COMPUTER NETWORKS; DATA SYSTEMS; DATA TRANSMISSION; DIRECTORIES; INTERPROCESSOR COMMUNICATION; INFORMATION SYSTEMS; ON-LINE SYSTEMS; PROTOTYPES
Downloads: 58
[image]The Prodigy Brothers On www.u.listen2myradio.com Logo Prototypes - Ainst
Designed By Ainst. 2012
Keywords: The Prodigy Brothers; www.u.listen2myradio.com; Logo; Prototypes
Downloads: 12
[texts]A device for testing cables - NON
A device for testing current paths is attachable to a conductor. The device automatically checks the current paths of the conductor for continuity of a center conductor, continuity of a shield, and a short circuit between the shield and the center conductor. The device includes a pair of connectors and a circuit to provide for testing of the conductive paths of a cable to be tested with the circuit paths of the circuit...
Keywords: ADAPTIVE OPTICS; TRANSMISSION; PHASED ARRAYS; SYSTEMS INTEGRATION; TELESCOPES; APERTURES; LASER BEAMS; MIRRORS; PROTOTYPES; TEST FACILITIES
Downloads: 104
[texts]Financial issues for commercial space ventures: Paying for the dreams - Egan, J. J
Various financial issues involved in commercial space enterprise are discussed. Particular emphasis is placed on the materials processing area: the current state of business plan and financial developments, what is needed for enhanced probability of success of future materials development efforts in attracting financial backing, and finally, the risks involved in this entire business area.
Keywords: DISPLAY DEVICES; PERIPHERAL VISION; AIRCRAFT MANEUVERS; ATTITUDE INDICATORS; EVALUATION; FLIGHT TESTS; PROTOTYPES; ROLL
Downloads: 72
[texts]A Catalog of Soft X-Ray Shadows, and More Contemplation of the 1/4 KeV Background - Snowden, S. L.
This paper presents a catalog of shadows in the 1/4 keV soft X-ray diffuse background 4 (SXRB) that were identified by a comparison between ROSAT All-Sky Survey maps and DIRB&corrected IRAS 100 micron maps. These ''shadows'' are the negative correlations between the surface brightness of the SXRB and the column density of the Galactic interstellar medium (ISIM) over limited angular regions (a few degrees in extent)...
Keywords: SYSTEMS ENGINEERING; DATA MANAGEMENT; BIBLIOGRAPHIES; DATA BASES; PROTOTYPES; INTERNETS; SUBROUTINE LIBRARIES (COMPUTERS)
Downloads: 100
[texts]Prototyping hard real-time Ada systems in a classroom environment - Luqi.;Shing, Man-Tak.;Barnes, P.;Hughes, G.
Title from cover
Keywords: ADA PROGRAMMING LANGUAGE; PROTOTYPES; REAL TIME; COMPUTER AIDED DESIGN; TEACHING METHODS
Downloads: 61
[texts]Improved composite material and method for production of improved composite material - NON
A laminated composite material with improved interlaminar strength and damage tolerance having short rods distributed evenly throughout the composite material perpendicular to the laminae is introduced. Each rod is shorter than the thickness of the finished laminate, but several times as long as the thickness of each lamina. The laminate is made by inserting short rods in layers of prepreg material, and then stacking and curing prepreg material with rods inserted therethrough.
Keywords: ARTIFICIAL INTELLIGENCE; MAN MACHINE SYSTEMS; ROBOTICS; ROBOTS; AUTONOMY; MACHINE LEARNING; MOBILITY; PROBLEM SOLVING; PROTOTYPES
Downloads: 87
[texts]Using Steady State CFD for Acoustic Predictions - Frendi, Kader
This report presents a semi-empirical model for acoustic predictions.
Keywords: ELECTRIC FIELDS; ROCKET FLIGHT; SOUNDING ROCKETS; FABRICATION; LAUNCHING; MECHANICAL ENGINEERING; PROTOTYPES; ROTATION; SIMULATION
Downloads: 93
[texts]Hierarchical Discrete Event Supervisory Control of Aircraft Propulsion Systems - Yasar, Murat
This paper presents a hierarchical application of Discrete Event Supervisory (DES) control theory for intelligent decision and control of a twin-engine aircraft propulsion system. A dual layer hierarchical DES controller is designed to supervise and coordinate the operation of two engines of the propulsion system. The two engines are individually controlled to achieve enhanced performance and reliability, necessary for fulfilling the mission objectives...
Keywords: FLIGHT CONTROL; ROTARY WING AIRCRAFT; VERTICAL TAKEOFF AIRCRAFT; VERTICAL TAKEOFF; SCHEDULES; PROTOTYPES
Downloads: 64
[texts]Multimegawatt thermionic reactor systems for space applications - Hill, P. R.
Design features and performance characteristics of thermionic reactor systems for space applications
Keywords: CONFIGURATION MANAGEMENT; CONSOLES; DISPLAY DEVICES; EQUIPMENT SPECIFICATIONS; PROTOTYPES; CONFERENCES; HARDWARE; HUMAN FACTORS ENGINEERING
Downloads: 121
[texts]UTILIZATION OF WIND POWER IN AGRICULTURE IN THE USSR - STEIN, D
WIND MOTORS ARE BEING USED IN RUSSIAN AGRICULTURE FOR MILLING AND PUMPING WATER. PLANS CALL FOR RAPID EXPANSION OF THE UTILIZATION OF SUCH POWER PLANTS. THE EXTENT OF PRESENT UTILIZATION, PROBLEMS, AND FORECASTS ARE OUTLINED.
Keywords: ACTUATORS; DIGITAL SYSTEMS; ELECTRIC CONTROL; HYDRAULIC CONTROL; AIRCRAFT CONTROL; CONTROL SURFACES; CONTROL VALVES; PROTOTYPES; RELIABILITY ENGINEERING
Downloads: 127
[texts]Axisymmetric Two-Dimensional Computation of Magnetic Field Dragging in Accretion Disks - Reyes-Ruiz, Mauricio
In this paper we model a geometrically thin accretion disk interacting with an externally imposed, uniform, vertical magnetic field. The accretion flow in the disk drags and distorts field lines, amplifying the magnetic field in the process. Inside the disk the radial component of the field is sheared into a toroidal component. The aim of this work is to establish the character of the resultant magnetic field and its dependence on the disk's parameters...
Keywords: FAILURE; EXPERIMENTATION; DATA PROCESSING; INJECTION; EVALUATION; COMPLEX SYSTEMS; ARCHITECTURE (COMPUTERS); CRASHES; DESTRUCTION; ERRORS; PROTOTYPES
Downloads: 71
[texts]Phase 1 Space Fission Propulsion System Design Considerations - Houts, Mike
Fission technology can enable rapid, affordable access to any point in the solar system. If fission propulsion systems are to be developed to their full potential; however, near-term customers must be identified and initial fission systems successfully developed, launched, and operated. Studies conducted in fiscal year 2001 (IISTP, 2001) show that fission electric propulsion (FEP) systems operating at 80 kWe or above could enhance or enable numerous robotic outer solar system missions of interes...
Keywords: WIND TUNNELS; DATA STORAGE; SUPERCOMPUTERS; WIND TUNNEL TESTS; COMPUTATIONAL GRIDS; PROTOTYPES; FLOW VISUALIZATION
Downloads: 79
[texts]Advanced Information Processing System (AIPS). System specification, revision 1 - NON
This specification sets forth the requirements for the design, development, fabrication, quality assurance, and evaluation of the Advanced Information Processing System (AIPS) Proof-of-Concept (POC) System, hereinafter referred to as the POC System. These requirements shall be the basis for the preparation of more detailed requirements to be included in: (1) subsequent revisions of the system specification, and in related system documents, such as interface control documents (ICD's); and (2) spe...
Keywords: COMPUTER PROGRAMS; PROJECT MANAGEMENT; PROTOTYPES; SOFTWARE ENGINEERING; ANALOGIES; DATA ACQUISITION; REQUIREMENTS
Downloads: 144
[texts]MS212--A Homogeneous Sputtered Solid Lubricant Coating for Use to 800 C - Sliney, Harold E.
Composite coatings containing chromium carbide, stable fluorides and silver were prepared by magnetron sputtering. The microstructure of the coatings is very homogeneous compared to that of plasma sprayed and sintered versions of the same chemical composition. Friction and wear of MS212-coated and baseline uncoated aluminum and Inconel X-750 are compared. At room temperature, the friction and wear of coated aluminum is dramatically better compared to the baseline...
Keywords: DATA SYSTEMS; DISPLAY DEVICES; ULTRASONIC SCANNERS; ATTENUATION COEFFICIENTS; WAVEFORMS; FREQUENCIES; MICROSTRUCTURE; PROTOTYPES
Downloads: 75
[texts]Contributions of Tropical Cyclones to the North Atlantic Climatological Rainfall as Observed from Satellites - Rodgers, Edward B.
The tropical cyclone rainfall climatology study that was performed for the North Pacific was extended to the North Atlantic. Similar to the North Pacific tropical cyclone study, mean monthly rainfall within 444 km of the center of the North Atlantic tropical cyclones (i.e., that reached storm stage and greater) was estimated from passive microwave satellite observations during, an eleven year period...
Keywords: PROTECTIVE CLOTHING; TECHNOLOGY TRANSFER; FIRE FIGHTING; EXTRAVEHICULAR ACTIVITY; SPACE SUITS; FLAMMABILITY; PROTOTYPES; TECHNOLOGY UTILIZATION
Downloads: 106
[texts]Meteorites, Microfossils and Exobiology - Hoover, Richard B
The discovery of evidence for biogenic activity and possible microfossils in a Martian meteorite may have initiated a paradigm shift regarding the existence of extraterrestrial microbial life. Terrestrial extremophiles that live in deep granite and hydrothermal vents and nanofossils in volcanic tuffs have altered the premise that microbial life and microfossils are inconsistent with volcanic activity and igneous rocks...
Keywords: AIR TRAFFIC CONTROL; PROBABILITY THEORY; FREE FLIGHT; WARNING SYSTEMS; FLIGHT CREWS; PROTOTYPES; MONTE CARLO METHOD; SIMULATORS
Downloads: 183
[texts]Star Formation as Seen by the Infrared Array Camera on Spitzer - Smith, Howard A.
The Infrared Array Camera (IRAC) onboard Spitzer has imaged regions of star formation (SF) in its four IR bands with spatial resolutions of approximately 2''/pixel. IRAC is sensitive enough to detect very faint, embedded young stars at levels of tens of Jy, and IRAC photometry can categorize their stages of development: from young protostars with infalling envelopes (Class 0/1) to stars whose infrared excesses derive from accreting circumstellar disks (Class 11) to evolved stars dominated by pho...
Keywords: SITUATIONAL AWARENESS; AIRCRAFT INSTRUMENTS; DISPLAY DEVICES; HELICOPTERS; EXPERT SYSTEMS; AIRCRAFT PILOTS; PILOT TRAINING; HYDRAULIC EQUIPMENT; PROTOTYPES
Downloads: 88
[texts]A Formal Methods Approach to the Analysis of Mode Confusion - Butler, Ricky W.
The goal of the new NASA Aviation Safety Program (AvSP) is to reduce the civil aviation fatal accident rate by 80% in ten years and 90% in twenty years. This program is being driven by the accident data with a focus on the most recent history. Pilot error is the most commonly cited cause for fatal accidents (up to 70%) and obviously must be given major consideration in this program. While the greatest source of pilot error is the loss of situation awareness , mode confusion is increasingly becom...
Keywords: DATA CONVERSION ROUTINES; INFORMATION RETRIEVAL; COMPUTER PROGRAMS; PROTOTYPES; ON-LINE SYSTEMS; LIBRARIES; DIGITAL TECHNIQUES; CD-ROM
Downloads: 62
[texts]Substitution Effects and Linear Free Energy Relationships during Reduction of 4- Benzoyl-N-(4-substituted benzyl)pyridinium Cations - Leventis, Nicholas
In analogy to 4-(para-substituted benzoyl)-N-methylpyridinium cations (1-X's), the title species (2-X's, -X = -OCH3, -CH3, -H, -Br, -COCH3, -NO2) undergo two reversible, well-separated (E(sub 1/2) greater than or equal to 650 mV) one-electron reductions. The effect of substitution on the reduction potentials of 2-X's is much weaker than the effect of the same substituents on 1-X's: the Hammett rho-values are 0.80 and 0.93 for the 1st- and 2nd-e reduction of 2-X's vs...
Keywords: ARCHITECTURE (COMPUTERS); PARALLEL COMPUTERS; INTERFACES; RELIABILITY ANALYSIS; COMPUTER TECHNIQUES; SEQUENTIAL COMPUTERS; PROTOTYPES; CYCLES
Downloads: 91
[texts]Thermographic Characterization of Impact Damage in SiC/SiC Composite Materials - Fox, Dennis S.
SiC/SiC composite materials targeted as turbine components for next-generation aero-engines are being investigated at NASA Glenn Research Center. In order to examine damage mechanisms in these materials, SiC/SiC coupons were impacted with 1.59 mm diameter steel spheres at increasing velocities from 115 m/s to 400 m/s. Pulsed thermography, a nondestructive evaluation technique that monitors the thermal response of a sample over time, was utilized to characterize the impact damage...
Keywords: PRODUCT DEVELOPMENT; TECHNOLOGY UTILIZATION; OXYGEN ATOMS; CLEANING; AEROSPACE TECHNOLOGY TRANSFER; PROTOTYPES; ORGANIC MATERIALS; RESIDUES
Downloads: 122
[texts]Characterization of Unsteady Flow Structures Around Tandem Cylinders for Component Interaction Studies in Airframe Noise - Jenkins, Luther N.
A joint computational and experimental study has been performed at NASA Langley Research Center to investigate the unsteady flow generated by the components of an aircraft landing gear system. Because the flow field surrounding a full landing gear is so complex, the study was conducted on a simplified geometry consisting of two cylinders in tandem arrangement to isolate and characterize the pertinent flow phenomena...
Keywords: TECHNOLOGY UTILIZATION; VOLTAGE CONVERTERS (DC TO DC); CRYOGENICS; PROTOTYPES; EFFICIENCY; NASA SPACE PROGRAMS
Downloads: 105
[texts]Measurement and modeling of dispersive pulse propagation in draw wire waveguides - Madaras, Eric I.
An analytical model of dispersive pulse propagation in semi-infinite cylinders due to transient axially symmetric end conditions has been experimentally investigated. Specifically, the dispersive propagation of the first axially symmetric longitudinal mode in thin wire waveguides, which have ends in butt contact with longitudinal piezoelectric ultrasonic transducers, is examined. The method allows for prediction of a propagated waveform given a measured source waveform, together with the materia...
Keywords: PROTOTYPES; COMPUTER AIDED DESIGN; TOLERANCES (MECHANICS); LAYERS; COMPUTERIZED SIMULATION; NONDESTRUCTIVE TESTS; CURL (MATERIALS); THICKNESS
Downloads: 78
[texts]System identification and model reduction using modulating function techniques - Shen, Ya
Weighted least squares (WLS) and adaptive weighted least squares (AWLS) algorithms are initiated for continuous-time system identification using Fourier type modulating function techniques. Two stochastic signal models are examined using the mean square properties of the stochastic calculus: an equation error signal model with white noise residuals, and a more realistic white measurement noise signal model...
Keywords: COMPUTER NETWORKS; PRODUCTIVITY; CONFERENCES; PROTOTYPES; SCHEDULING; VIDEO COMMUNICATION; WORKSTATIONS; COST EFFECTIVENESS; COSTS; MONITORS
Downloads: 111
[texts]NASA High-Reynolds Number Circulation Control Research - Overview of CFD and Planned Experiments - Milholen, W. E., II
A new capability to test active flow control concepts and propulsion simulations at high Reynolds numbers in the National Transonic Facility at the NASA Langley Research Center is being developed. This technique is focused on the use of semi-span models due to their increased model size and relative ease of routing high-pressure air to the model. A new dual flow-path high-pressure air delivery station has been designed, along with a new high performance transonic sem -si pan wing model...
Keywords: PROTOTYPES; THREE DIMENSIONAL MODELS; SCIENTIFIC VISUALIZATION; SOFTWARE ENGINEERING; PLANETARY ENVIRONMENTS; JAVA (PROGRAMMING LANGUAGE)
Downloads: 166
[texts]Development of Creep-Resistant NiAl(Ti,Hf) Single-Crystal Alloys - NON
Nickel-base superalloys are the current choice for high-temperature jet engine applications such as turbine blades and vanes. However, after more than five decades of use, nickel-base superalloys have reached their limit, since the operating temperatures in gas turbine engines are now approaching the melting temperature of these alloys. Thus alternative materials, such as lightweight NiAl intermetallic alloys with superior properties, (e.g., high melting temperature, high thermal conductivity, a...
Keywords: SPACECRAFT ELECTRONIC EQUIPMENT; CODERS; SATELLITE COMMUNICATION; COMMUNICATION EQUIPMENT; PULSE COMMUNICATION; DOWNLINKING; PROTOTYPES
Downloads: 99
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